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userfaultfd: non-cooperative: release all ctx in dup_userfaultfd_complete 

Don't stop running dup_fctx() even if userfaultfd_event_wait_completion
fails as it has to run userfaultfd_ctx_put on all ctx to pair against
the userfaultfd_ctx_get that was run on all fctx->orig in
dup_userfaultfd.

Link: http://lkml.kernel.org/r/20170224181957.19736-4-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrea Arcangeli 2017-03-09 16:16:54 -08:00 committed by Linus Torvalds
parent 9a69a829f9
commit 8c9e7bb7a4
1 changed files with 5 additions and 13 deletions
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16
fs/userfaultfd.c
View File

@ -527,16 +527,12 @@ out:
return ret;
}
static int userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
static void userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
struct userfaultfd_wait_queue *ewq)
{
int ret;
ret = -1;
if (WARN_ON_ONCE(current->flags & PF_EXITING))
goto out;
ret = 0;
ewq->ctx = ctx;
init_waitqueue_entry(&ewq->wq, current);
@ -552,7 +548,6 @@ static int userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
break;
if (ACCESS_ONCE(ctx->released) ||
fatal_signal_pending(current)) {
ret = -1;
__remove_wait_queue(&ctx->event_wqh, &ewq->wq);
break;
}
@ -573,7 +568,6 @@ static int userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
*/
out:
userfaultfd_ctx_put(ctx);
return ret;
}
static void userfaultfd_event_complete(struct userfaultfd_ctx *ctx,
@ -631,7 +625,7 @@ int dup_userfaultfd(struct vm_area_struct *vma, struct list_head *fcs)
return 0;
}
static int dup_fctx(struct userfaultfd_fork_ctx *fctx)
static void dup_fctx(struct userfaultfd_fork_ctx *fctx)
{
struct userfaultfd_ctx *ctx = fctx->orig;
struct userfaultfd_wait_queue ewq;
@ -641,17 +635,15 @@ static int dup_fctx(struct userfaultfd_fork_ctx *fctx)
ewq.msg.event = UFFD_EVENT_FORK;
ewq.msg.arg.reserved.reserved1 = (unsigned long)fctx->new;
return userfaultfd_event_wait_completion(ctx, &ewq);
userfaultfd_event_wait_completion(ctx, &ewq);
}
void dup_userfaultfd_complete(struct list_head *fcs)
{
int ret = 0;
struct userfaultfd_fork_ctx *fctx, *n;
list_for_each_entry_safe(fctx, n, fcs, list) {
if (!ret)
ret = dup_fctx(fctx);
dup_fctx(fctx);
list_del(&fctx->list);
kfree(fctx);
}